The invention relates to an improved tow bar assembly and attaching system where the individual tow bars are arranged in a V-configuration between the towing vehicle and the disabled vehicle. The invention allows the tow bars to be connected to the disabled vehicles without the need of a clevis. The improved tow bar better resists the compression and shock forces of towing and therefore can be made of lighter materials. The improved tow bar assembly is particularly useful for heavy vehicles weighing over 50 tons, but may be used for all-wheeled or tracked vehicles.
Prior art devices such as the invention described in U.S. Pat. No. 4,374,593, issued Feb. 22, 1983 to Roger R. Smith and James L. Celentino, show a two piece tow bar assembly with special end connectors that hook around a single towing pintle. The two piece design permitted interchangeable use of various tow bars and made mounting the tow bar a much easier process because each tow bar was only half the weight of earlier designs. One person could unload and mount the tow bar to a disabled vehicle unassisted.
The prior art device made use of a three piece vertical hook mechanism for attaching the rear of the tow bar to the disabled vehicle. A specialized eye connector was designed to fit the standard hook on the disabled vehicle. The hook could pivot vertically with respect to the eye member. An elongated loop attached to the rear of each tow bar engaged the hook. One problem with the prior art hook and loop attachment method is binding between the hook and loop when the towing and disabled vehicles turn, roll or pitch. The binding occurs because the pivoting points on the disabled vehicle are perpendicular to the vehicle's axis while the tow bars are angled at approximately 25.degree. from center. The result of this configuration is binding during towing and greater stress on these crucial pivoting points.
A second problem of the hook and loop fastening method is the play in the attaching means. The loop configuration allows the hook to travel in and out approximately 2 inches until it hits the ends of the loop. This travel occurs whenever the towing vehicle stops, starts or encounters a bump. When towing heavy vehicles, this travel imparts an enormous shock on the attaching points at each occurrence and can result in a premature failure of the tow bar.
Tow bar failures usually manifest themselves either by failure at the attaching points or at the center of the tow bar. Because bending forces concentrate at the midpoint of the tow bar bending of the bar can result in a column failure. By reinforcing this area of the tow bar with a composite winding, the tow bar can be made of a lighter material which eases installation and removal.
The major object of my invention is to provide for an improved attaching means for attaching the tow bar to the disabled vehicle. The improved connection geometry allows the tow bar to swing freely about an axis perpendicular to the front plane of the disabled vehicle without binding. A further object of my invention is to eliminate the travel in the attaching points and to absorb any shock by means of two springs attaching the towing pintle to the towing vehicle. A final object of the invention is to strengthen the tow bar in the critical central area by use of alternating composite windings.